.panda-btn {
  position: relative;
  width: 30px;
  height: 30px;
  margin-right: 5px;
  background-color: rgba(230, 230, 230, 0.8);
  border-radius: 30px;
  font-size: 0;
  transition: background 0.5s 0s, opacity .3s;
  overflow: hidden;
  cursor: pointer;
  backdrop-filter: blur(3px);
  will-change: background;
}
.panda-btn:hover {
  background-color: rgba(230, 230, 230, 1);
}
.panda-btn::before,
.panda-btn::after {
  content: '';
  position: absolute;
  border-radius: 30px;
  will-change: width, height, top, left, right, bottom;
}
.panda-btn::before {
  background-color: rgba(119, 119, 119, .618);
  animation: toggle-before 0.3s 0.3s forwards;
  z-index: 2;
}
.panda-btn::after {
  background-color: #e6e6e6;
  animation: toggle-after 0.3s;
  z-index: 1;
}
.panda-btn.theme--dark {
  background-color: rgba(119, 119, 119, .618);
}
.panda-btn.theme--dark::before {
  animation: toggle-before--dark 0.3s forwards;
}
.panda-btn.theme--dark::after {
  z-index: 3;
  animation: toggle-after--dark 0.3s 0.3s forwards;
}
@keyframes toggle {
  to {
    background-color: rgba(119, 119, 119, .618);
  }
}
@keyframes toggle-before {
  from {
    top: 15px;
    left: 15px;
    width: 0;
    height: 0;
  }
  to {
    top: 10px;
    left: 10px;
    width: 10px;
    height: 10px;
  }
}
@keyframes toggle-before--dark {
  from {
    top: 10px;
    left: 10px;
    width: 10px;
    height: 10px;
  }
  to {
    background-color: #2c2e30;
    top: 0;
    left: 0;
    width: 30px;
    height: 30px;
  }
}
@keyframes toggle-after {
  from {
    top: 10px;
    left: 10px;
    width: 10px;
    height: 10px;
  }
  to {
    top: 0;
    left: 0;
    width: 30px;
    height: 30px;
  }
}
@keyframes toggle-after--dark {
  from {
    top: 15px;
    left: 15px;
    width: 0;
    height: 0;
  }
  to {
    background-color: #777777;
    top: 10px;
    left: 10px;
    width: 10px;
    height: 10px;
  }
}
